Aluminum foil seals are in common use for sealing the mouths of bottles, especially bottles containing consumable products such as pharmaceuticals, food products, etc. The aluminum foil seal is adhered to the upper end of the bottle neck, which defines the mouth of the bottle, immediately following the filling of the bottle with the consumable product in question. These common seals accomplish two important functions, i.e. they first serve to ensure that no foreign material has entered the bottle after it has been filled with the intended product, and they second serve to prevent purposeful tampering, because access to the interior of the bottle cannot be achieved without destroying the seal.
These aluminum foil seals are available in a number of forms, including aluminum foil coated with polymer, and polymer coated aluminum foil laminated to paper. The polymer coating serves to facilitate adherence of the seal to the edge of the bottle neck such as by heat welding. The bottles commonly used are plastic bottle, although it is also possible to use a glass bottle with a polymer coated neck end. Such seals are also available coated with special polymer which will even adhere to uncoated glass.
A major problem of these prior seals is they are extremely difficult for the consumer to remove from the mouth of the bottle. There is nothing of which the consumer can grab hold in an attempt to remove the seal. Consequently, the consumer usually must use a tool such as a knife, or merely poke a finger through the seal. This in turn results in a second problem, i.e. the flexible aluminum seal is not completely removed from the edge of the bottle neck, and it is therefore ragged around the opening making it difficult to remove the product.
Solutions have been proposed including the formation of tabs along the edge of the seal which project beyond the neck of the bottle to help facilitate removal of the seal through grasping by the user. In one form, which has now been largely discarded by the art, a plurality of small protuberances are provided about the periphery, but these protuberances by necessity are no greater than the depth of the bottle screw threads so as to prevent such protuberances from becoming welded to the bottle cap or interfering with the screw threads. However, tabs or protuberances of that size are not of an adequate length to be easily grasped by the consumer, and therefore this solution to the problem has not proven successful.
It has also been proposed to use a bell shaped tab folded on top of the aluminum seal. This expedient provides a partial solution to the problem in that the bell shaped tab is sufficiently large so that it can be grasped by the consumer and will usually have sufficient strength so as to permit removal of the seal from the bottle. However, sometimes the seal will tear leaving the consumer with either insufficient remaining tab to grasp or no tab at all. Also, when a plastic bottle cap is used, steps must be taken to ensure that the tab does not seal to the cap, e.g. a secondary paper liner or wax paper liner will need to be used which increases the cost of the package. A major problem is that the manufacturer of a seal with such a tab requires substantially greater processing costs. Thus, either an odd shaped stamping die must be used, or two stamping dies are required, one for the bell shaped tab and one for the seal or body portion itself. Moreover, a second mounting device for assembly is necessary, i.e. one cannot use the same die for both stamping and mounting the seal within the cap. The coordination of this equipment is time consuming, difficult to maintain accurate, and expensive due to the number of operations required on different pieces of material.
French Pat. No. 2,327,161 shows the manufacture in a single stamping operation of an aluminum foil sesal having a tab, after which the seal is mounted onto the mouth of a tube and sealed thereto by induction heating. While the method of patent solves one of the problems mentioned immediately above, i.e. the problem of the use of either a complex die or separate dies to punch the two portions of the aluminum seal, it does not solve the remaining problems outlined above.